1. The overall response rate excludes schools who took part in the Realigning Children's Services Survey. For more details please see the SALSUS 2015 Technical Report available at: http://www.gov.scot/Topics/Research/by-topic/health-community-care/social-research/SALSUS
2. Scottish Health Survey 2015: Summary of key findings. http://www.gov.scot/publications/scottish-health-survey-2015-summary-key-findings/
3. Please see the SALSUS Mode Effect report for more detail at: http://www.gov.scot/Topics/Research/by-topic/health-community-care/social-research/SALSUS
4. The SALSUS Technical Report is available at: http://www.gov.scot/Topics/Research/by-topic/health-community-care/social-research/SALSUS
5. SALSUS 2015 Questionnaire is available at: http://www.gov.scot/Topics/Research/by-topic/health-community-care/social-research/SALSUS
6. The middle number of cigarettes smoked, after sorting all the responses in increasing order.
7. The median number for all is different to that for boys and girls combined due to a small number of pupils who did not state their gender.
8. The 2002 figures have been excluded from the chart as, in that year, there was no 'don't know' option meaning that a comparison cannot be made.
9. As the actual cost varies depending on the outlets and the brand, there is no 'correct' answer to this. In SALSUS, analysis is based on the 'Most Popular Price Category' according to the Tobacco Manufacturers' Association. This was £9.40 at 1 January 2016. http://www.the-tma.org.uk/tma-publications-research/facts-figures/uk-cigarette-prices/. Accessed 21 July 2016.
10. Results from previous waves are not completely comparable due to the addition of a 'don't know' option in 2015 and other changes in previous waves.
11. Given that 43% of regular smokers say that their parents do not know they smoke (Figure 4.1), a large proportion of those who say that they are not allowed to smoke at home will likely mean that they know/assume that they would not be allowed, rather than their parents having actively forbidden it.
12. A further 4% said they didn't regularly travel in a car